The Science Behind Sleep Cycles

There’s no doubt that sleeping seven to nine hours each night is good for your mental and physical health. To get a high-quality rest, it’s also essential that you smoothly transition through the four critical sleep cycles overnight. That entails reaching the deeper restorative sleep stages that allow your body and mind to heal and recharge.

The Stages of Sleep

The eight or so hours of regular sleep aren’t a single uniform phase of unconsciousness. Instead, a healthy overnight rest comprises multiple rounds of what experts call the “sleep cycle.” It involves four separate stages characterized by varying physical and mental activity levels.

Every night, a person will go through four to six sleep cycles. Each cycle usually lasts about 90 minutes, although cycle lengths can vary from person-to-person or night-to-night. Only one of the main phases is characterized by rapid eye movements (REM). The rest constitute non-REM (NREM) sleep patterns.

All the sleep stages help to regulate different bodily processes. As you go through these sleep cycles, your brain functions, such as learning and memory, undergo an optimization process for better daytime performance. Not only do your brain cells repair during sleep, but your immune system and heart health also get a boost.

Cycling through the four sleep stages also helps bolster energy conservation and insulin production. The psychological processes involved are a crucial part of keeping your body weight in check too.

Below are the four main sleep stages:

  • Stage 1 (NREM 1)– This is a short (one to five minutes) phase of sleep from which you may quickly transition to the next unless disturbed. Your body isn’t fully relaxed at this point, and you’ll be dozing off as your physical systems and brain start to switch off slowly. A slight disturbance may quickly wake you up during this phase.
  • Stage 2 (NREM 2)– N2 may last from 10–25 minutes, during which your body temperature drops and muscles relax. There’s no eye movement during this stage as your body and brain activities continue to decline. Throughout this sleep phase, it gets a little harder to wake up.
  • Stage 3 (NREM 3)– You’ll want to get the most out of your 20–40 minutes of N3 sleep because it’s the phase for critical bodily recovery and growth processes. This slow-wave sleep, delta sleep, or deep sleep stage also helps strengthen your immune system. It’s an opportunity to bolster your cognitive capabilities, including memory, learning, and creativity.
  • Stage 4 (REM)– During this 10–60 minute long sleep phase, your body is almost 100 percent switched off and relaxed, except for the eyes and the muscles that aid in breathing. It’s a period of rapid eye movements and high brain activity. Most vivid dreams happen during this stage, which accounts for roughly 20 percent of adults’ total sleep time and 50 percent of sleep in babies. Progressing through the final sleep phase can improve physical and mental health, with benefits like insightful thinking and emotional stability.

Scientific Tips for Getting Better Sleep

To get better sleep every night, you’ll want to avoid anything that may disrupt your circadian rhythm (sleep-wake cycle). Here are five recommendations worth exploring:

  1. Get Plenty of Daylight or Bright Light Exposure– Multiple studies show that daylight can help stimulate your brain, body, and hormones, enabling you to stay awake during the day and signaling your body when it’s time to sleep. It can help fix your sleep cycle, improving your sleep quality and duration.
  2. Keep Your Eyes Off Electronic Screens Before Bedtime– Turn off your TV, smartphone, or any other blue light sources about two hours before attempting to sleep. Exposure to this light late in the evening may keep your brain active longer, preventing you from progressing to deep sleep.
  3. Invest in a Comfortable Mattress– If hip, back, or spine discomforts are always keeping you up at night, you may not be sleeping on the right mattress type. Explore air foam technology mattress options that might let you enjoy the four crucial sleep stages every night.
  4. Avoid Alcohol at Night– Drinking alcoholic beverages late in the evening can trigger or aggravate sleep problems like apnea because it can inhibit your ability to breathe while sleeping. Having such disorders may prevent you from reaching therapeutic deep and REM sleep cycles.
  5. Avoid Caffeinated Beverages Late in the Day– These stimulants may reduce the secretion of melatonin. This hormone signals your body to relax, letting you get into deeper sleep phases faster.

Making the Most of the Four Sleep Cycles

Restorative sleep can enhance your mental and physical health in various ways. It enables your body and brain to repair and optimize critical functions like immunity against infection, learning, creative thinking, and memory retention. To harness the full healing power of a good night’s rest, you’ll want to go through all four sleep cycles.